1. Field of the Invention
The present invention relates to a method and apparatus for purging and disinfecting water for use in an air-conditioning system or a waste-gas scrubber; combined treatment water for recycling drainage water; water in which a water-soluble cutting oil, a water-soluble grinding oil, a water-soluble plastic oil, a coolant, etc. is dissolved for metalworking treatment; rinsing water for use in metal coating or surface treatment; water for use in sizing warp yarns of woven cloth; water for treating non-woven cloth; hydrophilous reaction water for emulsion polymerization and pearl polymerization; water for use in processes in a pulp plant or a papermaking plant; hot spring water; medicinal bath water; and pool water or other water for use in a plant, home, or public facility environment for humans or animals, such as a medical center or a food manufacturer. The invention is also useful in purging soil contaminated with agrichemicals, trichloro-ethylene, or dioxin, which are harmful to humans and animals.
2. Description of the Related Art
In the described field of the invention, heretofore, various methods using noxious microorganism-eradicating chemicals, such as chlorine-group, bromine-group and fluorine-group chemicals, sodium hypochlorite, ozone, hydrogen peroxide, or ultra-violet rays have been employed to kill microorganisms—such as germs, yeasts, fungi, and viruses, growing in a water circulation system and causing the degradation of water quality and the development of slime in circulating water. However, there has not yet been provided any inexpensive, useful method that has a wide spectrum of killing germs, yeasts, fungi, and viruses without producing drug-resistant microorganisms.
As the circulating water becomes dirty, the circulating water pipeline and water bath also become dirty and, as a result, an organic film is formed on the pipeline and bath walls, so that an adequate disinfections effect is difficult to achieve even when chemicals are put into the circulating water. Further, organic floaters adhere to the organic film so that microorganisms breed in the organic floaters and act as nutrients to form slime, causing clogging of the pipeline. As another problem, the slime when peeled off the pipeline walls could contaminate prospective products being processed.
The last-mentioned problem is particularly serious with the process of manufacturing paper pulp, during which a large volume of water is circulated and microorganisms, such as pulp organisms and yeasts in the pulp slurry tend to breed therein. The slime developed in the pulp slurry or white liquor in the water circulation system could be peeled off the system walls and cause drawbacks, such as staining, loss of paper product and/or breakage of a continuously traveling sheet. In many conventional methods, noxious-microorganism-eradicating chemicals, such as chlorine, bromine, fluorine, hydantoin, isothiazolon, glutaraldehyde, ozone, hydrogen peroxide, or ultraviolet rays are used. However, their operating cost is high and they are not entirely effective. Further, since part of the circulating water is drained, it could influence microorganisms in the drain water. Therefore, it would be necessary to use a moderate inhibitor rather than an antibacterial agent or fungicide disinfecting microorganisms, such as germs, yeasts, or fungi, which cause degradation of the drain water or the development of slime.
The present inventors filed the following patent applications for methods and apparatuses for purging and disinfecting pool water, bath water, water of 24-hour-open bath, fish pond water, pond water, air-conditioning water, car-wash drainage water, or combined treatment water, by electrolysis:    (1) Japanese Patent Application No. H05-087676 for apparatus for purging pool water or bath water;    (2) Japanese Patent Application No. H06-233739 for water purging method and apparatus;    (3) Japanese Patent Application No. H09-299084 for water quality purging method and mechanism;    (4) Japanese Patent Application No. H09-369487 for an electrolyzer;    (5) Japanese Patent Application No. H10-014089 for a water quality purging mechanism;    (6) Japanese Patent Application No. H10-016752 for a water quality purging mechanism;    (7) Japanese Patent Application No. H10-030555 for method and apparatus for purging water or drainage water;    (8) Japanese Patent Application No. H10-223702 for system for assessing dirt in water;    (9) Japanese Patent Application No. H10-340973 for combined treatment system and apparatus for purging combined treatment water;    (10) Japanese Patent Application No. 2000-168578 for an electrolyzer;    (11) Japanese Patent Application No. 2000-328779 for apparatus for purging water;    (12) Japanese Patent Application No. 2001-323356 for method and apparatus for treating wastewater or drainage water; and    (13) Japanese Patent Application No. 2001-369794 for an electrolyzer.
According to applications (1) and (2), although it is possible to purge and disinfect pool water or bath water by electrolysis using a titanium electrode plated with platinum, which is most resistant to corrosion, as the anode of an electrolyzer, the electrolyzing voltage would rise significantly in a short time if the electrolyzing load is large. According to application (5), by using a ferrite anode with a novel terminal-joining technique, it is possible to achieve a service life three-to-five times longer than when a platinum-plated titanium electrode is used under the same conditions.
According to applications (10) and (11) above, it is possible to provide a water-purging and disinfecting apparatus in the form of a compact, reliable electrolyzer which is easily attachable in a small environment, such as an existing bathtub or an ornamental fish tank. When the current value is increased in order to achieve a further-enhanced purging and disinfecting effect, terminals can be prevented from heating up. According to application (12) above, it is possible to provide a method and apparatus for treating waste water or drainage water containing agrichemicals, dioxin, etc.
According to these prior applications, some of the water or drainage water is introduced directly into the inter-electrode passageway (inter-electrode reaction section) of the electrolyzer so that organisms in the introduced water are oxidation decomposed to enhance the purging and disinfecting effect. However, these prior methods are not useful if water-soluble organisms essential to the processing water exist in the water. Another problem with the prior methods is that ordinary antibacterial agents or fungicide now in use would remain in the drainage water when added to the processing water, thus affecting microorganisms during a subsequent process for organisms in the drainage water.
Accordingly, there has been a need for an inexpensive, useful method which has a wide applicability for disinfecting microorganisms, such as germs, yeasts, fungi, and viruses growing in the water circulation system and causing degradation of water quality and the development of slime; and which can disinfect noxious microorganisms, such as germs, yeasts, fungi, and viruses, without giving rise to drug-resistant organisms and affecting any necessary chemicals, additives, etc. and can purge the water circulation system of such noxious microorganisms.